This variable causes fights. If you’ve recently upgraded, and then suddenly there are issues with the application – the reason is probably due to sql_mode defaults. sql_mode is how you get mysql to emulate the behavior of other SQL Servers, or to rise to the minimum standards in an RDBMS. It didn’t appear in MariaDB until 10.1.7, and the default increased in strictness by 10.2. sql_mode also affects user defined partitions in weird ways, so it is recommended that master/slave systems maintain the same modes.
Some of the interesting modes include: MSSQL, ORACLE and POSTGRESQL
Typical application issues come from invalid values: strings that are too long, numeric values out of range, etc. This typically comes from the application. Developers on a sprint and concerned about new functionality then act as if the database is the problem – all the while truncating values or continually entering some max value in the database. It happens at a corporate level all the time….